The present invention relates generally to a device for fixing a spine under treatment, and more particularly to a there-hooked device which is retained in the back of one spinal segment to facilitate the fixing of the spine.
There are a variety of conventional devices for use in fixing an injured or deformed vertebra. For example, the Halifax Tx Inter/aminar Clamp System of THE AME Corp. of the U.S. comprises a fastening bolt and a nut by means of which the spinal fixation is done. The spinal fixation effect of this prior art clamp system is poor in view of the fact that the nut is apt to become unfastened with the fastening bolt due to the intervertebral stress.
With the view of overcoming the deficiency of the prior art device described above, this inventor of the present invention developed two spinal fixation devices, which are respectively disclosed in the U.S. Pat. Nos. 5,454,812 and 5,380,326.
In light of lack of a spinal fixation device which is designed to fix only one spinal segment so as to facilitate the spinal surgery, this inventor of the present invention developed a vertebral fixation device, which is disclosed in the U.S. Pat. No. 5,507,747. This device is complicated in design in that it is formed of many component parts. In other words, the device tends to complicate and prolong the surgical operation, especially in a situation calling for treatment of multiple vertebrae.
It is the primary objective of the present invention to provide a three-hooked device for fixing one spinal segment. The three-hooked device comprises a main hooked seat and two extension hooks. The fixation of one spinal segment is attained by a main hooked portion of the main hooked seat and one hooked end of the two extension hooks.
It is another objective of the present invention to provide a three-hooked device for fixing any one of the spinal segments. The three-hooked device comprises a main hooked seat which is provided with two fastening rods extending therefrom for fixing the spinal segment in conjunction with the conventional fastening members, such as fixation rod, fixation screw, and the like.
In keeping with the principle of the present invention, the foregoing objectives of the present invention are attained by a three-hooked device comprising a main hooked seat, two extension hooks, and two fastening members. The main hooked seat is provided on one side near the undersurface with a main hooked portion, and near the uppersurface with two extension arms. The main hooked seat is further provided with two fastening rods extending therefrom. The main hooked seat serves to retain the spinal segment in such a manner that the main hooked portion is inserted into the spinal canal of the spinal segment, and that the two extension arms embrace the spinal projection of the spinal segment. The two extension hooks are provided at one end with a curved portion, and at other end with an adjustment portion. The curved portion serves to catch the spinal canal of the spinal segment, whereas the adjustment portion is adjustably fastened with the extension arm of the main hooked seat by the fastening member. The fastening member is formed of a sleeve and a tightening piece for fixing securely the adjustment portion which is adjustably received in the sleeve along with the extension arm.
In operation, the device of the present invention is retained in the back of any one of the spinal segments such that the main hooked portion of the main hooked seat and the curved portions of the two extension hooks hold the spinal canal of the spinal segment, and that the two fastening rods of the main hooked seat are fastened with the conventional fixation rods or fixation screws.
The component parts of the device of the present invention are made of a metal material implantable in the human body, such as the iron-based stainless steel 316 LVM (stainless steel 316 LUM), the titanium-based material Ti-6-4, the cobalt-molybdenum-chromium allow etc.
The features and the advantages of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of a preferred embodiment of the present invention with reference to the accompanying drawings.